Thousands of pro-Palestinian protesters forced an Israeli cargo ship to remain at sea an extra day, and continue to prevent dock workers from unloading its cargo.

The ship, Zim Piraeus, was supposed to dock at the Port of Oakland in California early Saturday morning, but was delayed until Saturday afternoon, apparently because of the scheduled protest, and did not dock until Sunday at 5 p.m., the San Francisco Chronicle reports.

Blocking the ship is part of a larger effort to impose sanctions on Israel for its intervention in Gaza, organizers told the Guardian. “With the recent attacks on Palestine … there’s been a lot of discussion locally, particularly with Aroc, on how to escalate our tactics,” said Lara Kiswani, executive director of the Arab Resource and Organizing Center, according to the Guardian.

When they encountered a police line at the port entrance Saturday, protesters began chanting “Hands up, don’t shoot,” according to the Guardian, in an effort to connect the violence in Gaza with the unrest in Ferguson, Mo., following the killing of an unarmed black teen by a police officer.

The ship finally docked Sunday afternoon, but protesters returned and picketed several Port gates. According to the San Francisco Chronicle, the dock workers did not show up for their shifts Sunday, and activists tweeted Monday afternoon that ongoing protests continue to prevent workers from unloading the ship.